Re: [GIT PULL] x86/apic changes for v2.6.38

[Yinghai Lu]

On Thu, Jan 6, 2011 at 5:21 PM, Randy Dunlap <randy.dunlap@xxxxxxxxxx> wrote:
> On Thu, 6 Jan 2011 16:17:10 -0800 Yinghai Lu wrote:
>
>> On Thu, Jan 6, 2011 at 3:53 PM, Linus Torvalds
>> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>> > On Thu, Jan 6, 2011 at 3:48 PM, Luck, Tony <tony.luck@xxxxxxxxx> wrote:
>> >> Untested on X86.  Builds and boots on ia64 (both normally and with
>> >> maxcpus=8 to limit the number of cpus).
>> >>
>> >> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
>> >
>> > Looks much better to me, and gets rid of that silly #ifdef that I reacted to.
>> >
>> > But no hurry, this looks low-priority. So let's make this go through
>> > the x86 tree and get merged later, after it has passed whatever normal
>> > tests that the -tip tree goes through. Ok?
>>
>> yes. x86 is safe. We have apicid_to_node[] array, and already check
>> apic id with MAX_LOCAL_APIC
>> in x86 version acpi_numa_processor_affinity_init().
>>
>> looks ia64 is using struct array with cpu idx for mapping
>>
>>         node_cpuid[srat_num_cpus].phys_id =
>>             (pa->apic_id << 8) | (pa->local_sapic_eid);
>>         /* nid should be overridden as logical node id later */
>>         node_cpuid[srat_num_cpus].nid = pxm;
>>         cpu_set(srat_num_cpus, early_cpu_possible_map);
>>         srat_num_cpus++;
>>
>> but it does not check the boundary of that array...
>>
>> struct node_cpuid_s node_cpuid[NR_CPUS]..
>>
>> so if some one try to boot kernel with small NR_CPUS on bigger IA64
>> system, could get some variables node_cpuid[]...
>>
>> Assume Tony will have another patch for IA64 to check that before
>> apply this patch.
>>
>> sth like
>>
>> Index: linux-2.6/arch/ia64/kernel/acpi.c
>> ===================================================================
>> --- linux-2.6.orig/arch/ia64/kernel/acpi.c
>> +++ linux-2.6/arch/ia64/kernel/acpi.c
>> @@ -477,6 +479,11 @@ acpi_numa_processor_affinity_init(struct
>>       if (!(pa->flags & ACPI_SRAT_CPU_ENABLED))
>>               return;
>>
>> +     if (srat_num_cpus >= NR_CPUS) {
>> +             printk(KERN_WARNING "NR_CPUS (%d) is too small, not all cpus used.
>> %d\n", NR_CPUS);
>
>                                                                        CPUs used.
>
> Don't need %d 2 times.
>
right.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/